Podcast
Questions and Answers
What is the typical particle diameter range for most pharmaceutical suspensions?
What is the typical particle diameter range for most pharmaceutical suspensions?
Which method is best for producing drug powders with a size of about 10-50 micrometers?
Which method is best for producing drug powders with a size of about 10-50 micrometers?
What is a potential issue when reducing particle size too much?
What is a potential issue when reducing particle size too much?
Which particle shape produces a more stable suspension?
Which particle shape produces a more stable suspension?
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Which of the following agents is NOT used to thicken the dispersion medium of a suspension?
Which of the following agents is NOT used to thicken the dispersion medium of a suspension?
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What is the primary function of fluid energy grinding?
What is the primary function of fluid energy grinding?
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Which characteristic of small particles can lead to stability issues in suspensions?
Which characteristic of small particles can lead to stability issues in suspensions?
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What term describes a loose aggregation of particles held together by weak bonding forces?
What term describes a loose aggregation of particles held together by weak bonding forces?
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What is one consequence of using fine particles in suspensions?
What is one consequence of using fine particles in suspensions?
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Which method is specifically used for producing ultra-fine particles for parenteral suspensions?
Which method is specifically used for producing ultra-fine particles for parenteral suspensions?
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What is the primary mechanism involved in fluid energy grinding?
What is the primary mechanism involved in fluid energy grinding?
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What is a key advantage of using carboxymethylcellulose in suspensions?
What is a key advantage of using carboxymethylcellulose in suspensions?
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In producing pharmaceutical suspensions, why are symmetrical barrel-shaped particles preferred?
In producing pharmaceutical suspensions, why are symmetrical barrel-shaped particles preferred?
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What is one drawback of using mortar and pestle for particle size reduction?
What is one drawback of using mortar and pestle for particle size reduction?
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Which process is necessary to produce particles under 10 micrometers in diameter?
Which process is necessary to produce particles under 10 micrometers in diameter?
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What effect do thickening agents like methylcellulose have on the suspension?
What effect do thickening agents like methylcellulose have on the suspension?
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Study Notes
Pharmaceutical Suspensions: Particle Size and Stability
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Particle Size Range: Most pharmaceutical suspensions contain particles between 1 and 50 µm.
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Micro Pulverization: A rapid and inexpensive method to produce fine drug powders (10-50 µm) using high-speed mills. Suitable for oral and topical suspensions.
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Fluid Energy Grinding/Jet Milling/ Micronizing: Used to create particles smaller than 10 µm. High-velocity compressed air shears particles in a confined space, creating micronized particles. Suitable for parenteral or ophthalmic suspensions.
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Spray Drying: Produces extremely small particles. A solution is sprayed into a cone-shaped apparatus where heated, dry air rapidly dries the solution. Mortar and pestle methods can't achieve this level of particle size control.
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Particle Size and Settling: Reducing particle size slows settling but extremely fine particles can form a compact cake. Avoiding excessive fineness is important.
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Particle Shape and Stability: Particle shape affects caking and stability. For example, symmetrical barrel-shaped particles are more stable than needle-shaped ones.
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Flocculation: Intentional formation of a loose aggregation (floc) of particles, held together by weak bonds, prevents rigid cohesion.
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Suspension Thickening Agents: Substances like carboxymethylcellulose, methylcellulose, microcrystalline cellulose, polyvinyl pyrrolidone, xanthan gum, and bentonite thicken the dispersion medium to aid in suspending the particles.
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Description
Explore the crucial aspects of pharmaceutical suspensions, focusing on particle size and stability techniques. Learn about methods like micro pulverization, jet milling, and spray drying, and their impact on suspension performance. Understand how particle size influences settling properties and overall effectiveness in formulations.
